Treatment of pyritic ores.



King of Great Britain and Ireland, residing i is i rrnn sirairns rairnar @FFXQEQI WILLIAM BLAUKMO'RE AND ALFRED HOWARD, OF LC'NDO N, ENGLEND, ASSZGNURS TO THE T. E. ORE SYNDICATE LIMITED. OF

LONDON, ENGLAND.

To all whom zit may concern/.-

Be it known that We, NILLrAM BLACK- MORE and ALFRED HOWARD, sub ects of the at London, England, have invented new and useful Improvements in the Treatment of Pyritic Ores Containing Gold, Silver, or other Valuable Metals, of which the following is a specification.

This invention relates to a process of treatment of pyritic ores containing gold, silver, or other valuable metals, and has for its object the of the iron pyritesfroim such ores, enabling the recovery of the valuable metals to be eiiected in a very simple manner at a low cost and with no risk 01" losing any of the valuable contents of such ores, as has been the case in the past.

To carry the invention into eil'ect, the ore is pulverized to about a thirtv mesh and is then oxidized in a furnace ata temperature of about 800 Fahrenheit. by passing steam and air in regulated quantities through the furnace, so as 1/0 come into contact with the heated ore contained in the said furnace, the amount passed through the furnace being regulated according to the anion; 1 of iron pyrites in the ore under treatment. The steam is added to modify the oxidizing action of the air and in such proportion as to prevent excessive local reaction. The eiiect of this treatment is to convert the rites into either a nor l basic so; a mixture of sulfate With o d of the operation is in, produwion of a i ii ti The reaction is earrie the iron pyrites is sulii is to say, oxidized to the no maximum production of sulfate Wl be economically obtained from the. is reached -this is" i suitable tests reaction is cor iron compounds slightly soluble in Water, and to remove 'ieni by solution in Water cannot be satisfactorily carried out commercially. Ne therefore leach the roasted ore With Water to which has been added sulfuric or other acid liquors to cause the iron to pass into solution in a r asonable is found tl Specification of Letters Patent. Annlication filed March 27,1906. Serial No- 308.1%;1-

FYHlTlG GEES.

Patented Dec. 25, less. a

be achieved by a solution containing five per cent'. of sulfuric acid; but it must be-cle'arly understood that satisfactory results canbe obtained by using an increasedquantity of Weaker solution. Under the above treat ment We find that the copper, cobalt, and nickel, if any of these are present in the ore, are dissolved by the acid solution in addition to the iron and can be separated and recovered by ordinary precipitants for these metals, leaving the iron unaffected in the so-' lution. After separation from the l lquor the solid residue containing the gold, silver, or other valuable metal can be treated by suitable extraction processes. For example, in a gold and silver ore the residues can be treated for the recovery of old and silver by the ordinary cyanid or c orination or other known methods. In the case of ores containing' lead or zinc the residues are further treated for the recovery of these metals by ordinary lead or zinc smelting rocesses.

The acid liquors necessary for the above solution can be produced as a by-product of. the process by passing the sulfurous gases evolved during the ro asting treatment throu h suitable condensing-towers or directly a sorbing them by water with or without a fur-Q ther addition of air or other oxidizing agents, and we rind that this part of the rocess is an important step to the econoinica elimination oi the iron from the ores.

.ving new particularly described and as tained t1 nature of our said invention what manner the same is to be per-- the treatment of pyri .c cry of valuable metals con-- in, consisting of the roasting of ed ore at a temperature of about 13a l the pulv riz l viilnenheit in the presence of an oXi-' dining agent consisting of air and steam so a" c vert the suliid or iron into normal or r .e of the leacning of the ore in acid .l. i to dissolve the iron sulfate, and of the anon of th' solution from the solid residue containing tne valuable metals, substantially as described.

In a process for the treatment of pyritic ores for the recovery of valuable metals contained therein consisting of the roasting of the pulverized c 2 at a temperature of time. We have found practical r x'lltS can. i about 800 Fahrenheit in the presence of an oxidizing agent consisting of air and steam so as'to convert the sulfid of iron into normal or basic sulfate of the leaching of the ore in acid. liquors to dissolve the iron sulfate and of the separation of the solution from the solid residue containing the valuable metals, the collection of the sulfurous gases evolved by the roasting treatment and their absorption by water to be used as the acid liquors in the process of solution of the iron sulfate, substantially as described.

3. A process for the treatment of pyritic ores containing gold, silver and other metals such as iron, cobalt, copper, or nickel consisting' of the roastin of the pulverized ore at a temperature of about 800 Fahrenheit in the presence of an oxidizing agent consisting of air and steam so as to convertthe iron, copper, cobalt or nickel into sulfates the leaching of those sulfates in liquors containing sulfuric acid, and the treatment of the said liquors by precipitants to recover the metals therefrom, and'the after treatment RICHARD A. IIOFFMANTN, ALBERT T. ROPER. 

